Lager Fermentation questions: seems slow - Reused slurry from last batch

[sleepystevenson]

I brewed 27 gal of a German Pils on Saturday, split into (2) half barrel keg fermenters with an OG of 1.047. In each fermenter, approximately 13 gallons of wort, I pitched the saved slurry from my last batch - one 34/70 and the other S23. I had damn near a full quart mason jar of each slurry (3/4 was a thick slurry with a 1/4 beer on top) into each fermenter, which I collected when I kegged the previous batch (Vienna Lager - slightly higher OG 1.052ish). The slurry was stored in my fridge for about 2-2.5 weeks. I pulled the slurry out and warmed up to fermentation temp of 54 F before pitching.

Fermentation seems like it is slow. On the first batch, I had slow blowoff tube activity in 24 hrs. This batch I have had virtually none after 2 days. You could get some bubbles out of the tube if you picked the tube up a little, but no active bubbling. There was the normal, expected yeasty smell in the temp controlled fridge that I ferment in on day 2. Last night, 2 days after pitching, I disconnected the tri clover blow off connection and looked into the fermenter. Their was a definite krausen on the top of each.

This morning, 2.5 days after pitching, I decided to pull a sample and take a gravity reading. The gravity had gone from 1.047 to 1.038 for the 34/70 and from 1.047 to 1.035 for the S23. I expect the final gravity to be around 1.010, so the 34/70 is about 24% complete and the S23 is about 32% complete

Does this seem slow to any of you lager brewers?? If so, I am considering driving over to the LHBS and buying a couple extra packs of each yeast and re-hydrating and pitching it tonight after work.

Thanks for the help in advance!

 

[CascadesBrewer]

Have you have success repitching that amount of slurry before? Based on my experience it feels like an underpitch. I typically will pitch a 16 oz jar of slurry into a 5.5 gal batch ale...scaling that up to 13 gals and doubling the pitch rate for a cool fermented lager would be more than 32 oz. It would depend a lot on how much yeast vs trub is in the harvested yeast. I have only brewed a few lagers myself, but a 2 day lag times it not too unusual.

Since you are through the lag phase and the beer is fermenting, I would not add more yeast myself. It might be a good idea to check on the batch once or twice over the next week to make sure it seems to be progressing.

 

[rburrelli]

I seem to have similar lag phase times with my lagers. 48 hours is not abnormal for a cooler pitched lager yeast IMHO.